<template>
  <!--
  重点:
    1. 解决javascript对于多位数字的失真问题
    2. 利用函数产生浏览器报错
    3. 获取图片的 url 列表
    4. 实现图片预览效果
    5. 关注 / 取关操作的组件化
    6. 掌握依赖注入
-->
  <div class="article-container">
    <!-- 导航栏 -->
    <van-nav-bar
      class="page-nav-bar"
      left-arrow
      title="黑马头条"
      @click-left="$router.back()"
    ></van-nav-bar>
    <!-- /导航栏 -->

    <div class="main-wrap">
      <!-- 加载中 -->
      <div class="loading-wrap" v-if="loading">
        <van-loading color="#3296fa" vertical>加载中</van-loading>
      </div>
      <!-- /加载中 -->

      <!-- 加载完成 -->
      <template v-else>
        <!-- 加载完成-文章详情 -->
        <div class="article-detail markdown-body" v-if="article.title">
          <!-- 文章标题 -->
          <h1 class="article-title">{{ article.title }}</h1>
          <!-- /文章标题 -->

          <!-- 用户信息 -->
          <van-cell class="user-info" center :border="false">
            <van-image
              class="avatar"
              slot="icon"
              round
              fit="cover"
              :src="article.aut_photo"
            />
            <div slot="title" class="user-name">{{ article.aut_name }}</div>
            <div slot="label" class="publish-date">
              {{ article.pubdate | relativeTime }}
            </div>
            <!-- **  关注 / 取关组件  ** -->
            <!-- <follow-user
            class="follow-btn"
            :user-id="article.aut_id"
            :is-followed="article.is_followed"
            @update-isFollowed="article.is_followed = $event"
            ></follow-user> -->
            <!-- 简化版本 -->
            <!--
              v-model 原理:
              默认为子组件出入参数 :value="article.is_followed"
              并调用 @input="article.is_followed = $event"
            -->
            <follow-user
              class="follow-btn"
              :user-id="article.aut_id"
              v-model="article.is_followed"
            ></follow-user>
          </van-cell>
          <!-- /用户信息 -->

          <!-- 文章内容 -->
          <div
            class="article-content"
            v-html="article.content"
            ref="article-content"
          ></div>
          <van-divider>正文结束</van-divider>
          <!-- **  评论组件  ** -->
          <!-- vant 库更新,默认不做滚动检查 -->
          <comment-list
            @load-success="totalCommentCount = $event.total_count"
            :source="article.art_id"
            :list="commentList"
             @reply-click="onReplyClick"
          />
        </div>
        <!-- /加载完成-文章详情 -->
        <template v-else>
          <!-- 加载失败：404 -->
          <div class="error-wrap" v-if="errStatus && errStatus === 404">
            <van-icon name="failure" />
            <p class="text">该资源不存在或已删除！</p>
          </div>
          <!-- /加载失败：404 -->

          <!-- 加载失败：其它未知错误（例如网络原因或服务端异常） -->
          <div class="error-wrap" v-else>
            <van-icon name="failure" />
            <p class="text">内容加载失败！</p>
            <van-button class="retry-btn" @click="getArticle"
              >点击重试</van-button
            >
          </div>
          <!-- /加载失败：其它未知错误（例如网络原因或服务端异常） -->
        </template>
      </template>
    </div>

    <!-- 底部区域 -->
    <!-- 方式1 将子组件的 required 属性去掉 -->
    <!-- 直接使用方式2 在数据还没拿到之前,不渲染整个底部栏 -->
    <!-- 方式3 将整个底部栏放到文章加载成功后的html结构后面 -->
    <div class="article-bottom" v-if="article.title">
      <van-button
        class="comment-btn"
        type="default"
        round
        size="small"
        @click="isPopupShow = true"
        >写评论</van-button
      >
      <van-icon name="comment-o" :info="totalCommentCount" color="#777" />
      <!-- **  收藏组件  ** -->
      <collect-article
        v-model="article.is_collected"
        :article-id="article.art_id"
      />
      <!-- **  点赞组件  ** -->
      <like-article v-model="article.attitude" :article-id="article.art_id" />
      <van-icon name="share" color="#777777"></van-icon>
    </div>
    <!-- 发布评论弹出层 -->
    <van-popup v-model="isPopupShow" position="bottom">
      <comment-post :target="article.art_id" @post-success="onPostSuccess"></comment-post>
    </van-popup>

    <!-- 回复评论弹出层 -->
    <van-popup  v-model="isReplyShow" position="bottom" style="height: 100%;">
      <!-- v-if="isReplyShow" 主要用于销毁 <comment-reply /> 组件 -->
      <!--
        为什么要销毁该组件?
          弹出层是懒加载的,激活就会被渲染,但关闭不会被销毁(也就意味着组件不会重新生成,也就不会重新获取数据)
          每次打开时所访问到的都是之前的数据.
          直接利用条件渲染的特性来完成弹出层内组件的重新加载(重新发请求获取数据)
      -->
      <comment-reply v-if="isReplyShow" :comment="currentComment" @close="isReplyShow = false"></comment-reply>
    </van-popup>
    <!-- /底部区域 -->
  </div>
</template>

<script>
import { getArticleById } from '@/api/articles.js'
import 'github-markdown-css/github-markdown.css'
// 图片预览组件
import { ImagePreview } from 'vant'
// 引入关注 / 取关组件
import followUser from '@/components/follow-user.vue'
// 收藏组件
import CollectArticle from '@/components/collect-article.vue'
// 点赞组件
import LikeArticle from '@/components/like-article.vue'
// 评论组件
import CommentList from '@/views/article/components/comment-list.vue'
// 弹出层发布评论组件
import CommentPost from './components/comment-post.vue'
// 回复评论组件
import CommentReply from './components/comment-reply.vue'

export default {
  name: 'ArticleIndex',
  components: {
    followUser,
    CollectArticle,
    LikeArticle,
    CommentList,
    CommentPost,
    CommentReply
  },
  // 依赖注入
  provide () {
    return {
      articleId: this.articleId
    }
  },
  props: {
    articleId: {
      // 直接通过地址栏访问传过来的是字符串
      // 点击文章进行路由跳转传过来的是数字类型
      type: [String, Number, Object],
      required: true
    }
  },
  data () {
    return {
      // 文章详情
      article: {},
      loading: true,
      errStatus: undefined,
      totalCommentCount: 0,
      isPopupShow: false,
      // 把 comment-list 的评论列表拿到父组件中操作
      commentList: [],
      isReplyShow: false,
      currentComment: {}
    }
  },
  created () {
    this.getArticle()
  },
  methods: {
    async getArticle () {
      this.loading = true
      try {
        // 高级自定义报错
        // if (Math.random() > -1) {
        //   throw new function () {
        //     this.response = {
        //       status: 403
        //     }
        //   }()
        // }
        const { data: { data } } = await getArticleById(this.articleId)
        this.article = data
        setTimeout(() => {
          const imgs = this.$refs['article-content'].querySelectorAll('img')
          const images = []
          imgs.forEach((img, index) => {
            images.push(img.src)
            img.onclick = () => {
              // 预览图片的列表
              ImagePreview({
                images,
                // 图片的初始位置
                startPosition: index
              })
            }
          })
        }, 0)
      } catch (error) {
        if (error && error.response.status === 404) {
          this.errStatus = 404
        } else {
          this.errStatus = 500
        }
        console.error(error)
      }
      this.loading = false
    },
    onPostSuccess (data) {
      // 关闭提交评论弹出层
      this.isPopupShow = false
      // 添加数据到评论列表
      this.commentList.unshift(data.new_obj)
    },
    onReplyClick (comment) {
      this.currentComment = comment
      this.isReplyShow = true
    }
  }
}
</script>

<style lang="less" scoped>
.article-container {
  .main-wrap {
    position: fixed;
    left: 0;
    right: 0;
    top: 92px;
    bottom: 88px;
    overflow-y: scroll;
    background-color: #fff;
  }
  .article-detail {
    .article-title {
      font-size: 40px;
      padding: 50px 32px;
      margin: 0;
      color: #3a3a3a;
    }

    .user-info {
      padding: 0 32px;
      .avatar {
        width: 70px;
        height: 70px;
        margin-right: 17px;
      }
      .van-cell__label {
        margin-top: 0;
      }
      .user-name {
        font-size: 24px;
        color: #3a3a3a;
      }
      .publish-date {
        font-size: 23px;
        color: #b7b7b7;
      }
      .follow-btn {
        width: 170px;
        height: 58px;
      }
    }

    .article-content {
      padding: 55px 32px;
      /deep/ p {
        text-align: justify;
      }
    }
  }

  .loading-wrap {
    padding: 200px 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #fff;
  }

  .error-wrap {
    padding: 200px 32px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background-color: #fff;
    .van-icon {
      font-size: 122px;
      color: #b4b4b4;
    }
    .text {
      font-size: 30px;
      color: #666666;
      margin: 33px 0 46px;
    }
    .retry-btn {
      width: 280px;
      height: 70px;
      line-height: 70px;
      border: 1px solid #c3c3c3;
      font-size: 30px;
      color: #666666;
    }
  }

  .article-bottom {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    justify-content: space-around;
    align-items: center;
    box-sizing: border-box;
    height: 88px;
    border-top: 1px solid #d8d8d8;
    background-color: #fff;
    .comment-btn {
      width: 282px;
      height: 46px;
      border: 2px solid #eeeeee;
      font-size: 30px;
      line-height: 46px;
      color: #a7a7a7;
    }
    .van-icon {
      font-size: 40px;
      .van-info {
        font-size: 16px;
        background-color: #e22829;
      }
    }
  }
}
</style>
